1. Field of the Invention
This invention relates to a vacuum switch which comprises a gas-tight sealed evacuated envelope having therein a stationary contact element and a movable contact element which is movable towards and away from the stationary contact element, and in which at least one of the contact elements consists of a disc-shaped contact portion and a bush-shaped portion which is connected to or integral with the disc-shaped portion, a conductor being present within the bush-shaped portion and connected in series with the associated contact element so as to produce an electric field in order to improve the current interruption characteristics of the vacuum switch. A vacuum switch of this kind is described in U.S. Pat. No. 3,082,307.
2. Description of the Prior Art
The known vacuum switch comprises an evacuated, insulating cylindrical envelope which is sealed by metal end plates, and includes a stationary contact element and a contact element movable towards or away from the stationary element within the envelope, at least one of the contact elements being provided with a bush-shaped contact portion connected in a gas-tight manner through the respective metal end plate. This bush-shaped contact portion may contain a conductor connected to the associated contact element, the conductor generating a magnetic flux at the contact area of the cooperating contact elements. This magnetic flux acts to improve the current-interruption characteristics of the vacuum switch.